body,html{
    margin:0;
    padding:0;
}

#main{
    margin:20px auto;
    width:260px;
}

#calc{
    margin-left:40px;
    width:70px;
}

span{
  color:red;
  margin-left:5px;
}

input{
    margin:5px 0;
}

#width-validate,#height-validate{
  color:red;
  margin-left:40px;
}
